Serialization of binary data with no content type in JSON format

[jskeet]

I'm trying to adjust the C# JSON serializers to take account of #861 and #881. I'm struggling on a couple of corner cases though, around binary data.

The JSON event format says that a serializer has to distinguish between binary data and non-binary data (to know which data property to populate) and also that the default content type (if otherwise unspecified) should be application/json. The placement of the defaulting (which was my own sentence!) is alongside the "not binary" case.

What does this mean for the structured mode encoded form of a CloudEvent with binary data but no data content type? Should a data content type of application/json be used anyway? Do we expect deserialization to cope with a JSON content type but binary data? (Just assume that the binary data is UTF-8-encoded text?)

It's possible that this kind of corner case doesn't need to be handled the same way by every SDK, of course...

[duglin]

@jskeet just to make sure I'm following the scenario... are you talking about a CE that looks like:

Content-Type: application/cloudevents+json

{
    "specversion" : "1.0",
    "id": "123",
    "source": "urn:uuid:6e8bc430-9c3a-11d9-9669-0800200c9a66",
    "type" : "com.example.someevent",
    "data_base64": "aGVsbG8gd29ybGQK"
}

If so, are you asking if the receiving SDK is supposed to treat the decoded "aGVsbG8gd29ybGQK" as json? I think the answer is "no" and the SDK shouldn't make any assumptions about it. It should treat it as an array of bytes.

[jskeet]

Nope, that's fine - it's only the data property. I expect I've just misremembered what was agreed, which would be great. Hopefully this can be cleared up really quickly in the meeting.

[jskeet]

Whoops - the above comment was written in a hurry, not noting that it's the wrong issue. (I was thinking of #934.)

Yes, you've got it exactly right, and I agree - I think we should only default to application/json for structured events where data is populated rather than data_base64.

[duglin]

We agreed to close this on the 2/17 meeting. @jskeet reopen if I got that wrong